learn metalworking.

“Watch one, do one, teach one” is supposedly the way surgery is taught. I did the same for metalworking. Afriend needed a hole drilled in the center of a steel rod, but couldn’t get a straight or centered hole drilled with his cordless drill. I invited him by to try it out with my little lathe.

Setup was a bit of a challenge; the rod was 18 inches long, so we stuck one end in the lathe’s chuck, and caught the other end in a hole in a block of wood clamped to the workbench. Even with our hacked setup, we got the work done. I showed my friend how to use a cutoff tool to cut the poorly drilled end off, then face the rod, center drill it, and drill the needed hole. We then pulled the rod out of the lathe, threaded the hole, and he went off on his way with a better understanding of machining.

It’ll be interesting to see what his next metalworking project will be!

So far, all my metalworking has been done on a tiny hobby lathe – 35 pounds, and small enough to fit in a cupboard. The latest project for the live steam locomotive (turning the main wheels/drivers) is way too big for the little lathe, so I needed to find a bigger machine.

Luckily, there’s this place called TechShop in Silicon Valley; for $30/day or $125/month, you can use all the cool tools they’ve got there. Laser cutters? Yup. Bridgeport mills and real lathes? Yes. Plasma cutter? Computer-controlled routers? Bending brakes and sheet metal cutters? Yup.

I finally went in this week and joined, and am making progress. I was a bit surprised how my work with the tiny lathe transferred so easily. I had to learn the controls, and had to learn how to switch belts to change speed, but otherwise it was a lot like my tiny lathe.

It’s also fun because there’s other people building things there too. It’s fun to share conversations over the work table, and see the high school kids building some sort of super-efficient car.

Once I’ve used the lathe, then it’ll be time to find some projects for the laser cutter.

I’ve done some silversmithing before, so maybe that’s a tad bit different. I would love to learn how to do this on a LARGE scale though to create amazing sculptures for my yard.

Wow, didn’t expect that response from someone who wasn’t a relative.

I’m still on my “go off to lunch with friends as often as possible” kick, and so I dropped a note to the guy that used to be in charge of our department at my last job suggesting lunch one day. We ended up catching up; I got to hear about his current projects (for he’s thinking of working in a different industry), and he got to hear about what I’ve been doing over the last several months.

I mentioned the metalworking and machining work, and told him about shaping metal, and using a lathe, and all the fun insights I’m seeing about engineering. (The biggest one: as a programmer, it’s really strange to be in a world where the person creating the design isn’t the same person as the person who’s actually building the thing, and where they both want to think about and describe the world in very different ways.)

He listens to me politely, and then says something along the lines of “You’re being safe, right? Nothing’s worth a finger.”

I assured him I was being careful, but was a little surprised that a former boss was sounding a bit like my parents. Did he know someone who’d gotten injured in a shop accident, or did the idea of sharp chunks of spinning metal just seem a bit dangerous?

And yes, I keep reminding myself that nothing’s worth a finger. Or even a bad cut. I’m getting better about filing down edges after machining just to make sure that the finished pieces are easy to handle.

So when I started with machining, I never thought I’d have to worry about… splinters.

Machining likes to “peel” bits of metal off kind of like paper from a roll. If you turn or drill aluminum or some steel, you get long, thin ribbons of metal if you’re cutting right. When machining, you get continuous chips matching the cut of the cutting tool.

Some metals don’t behave that way, and instead break off little “slivers” of metal. Brass is one of the metals most known for this. Because machining produces a lot of chips that collect around the machine, it’s not hard to find splinters in your hands as you work. Not fun.

On a current project, I was too cheap/impatient to get decent steel, but instead bought some .25×1.25 inch steel from the hardware store. It turns out this was “hot rolled” steel with a rough, blackened finish. Worse, it was really hard stuff, so it wouldn’t cut cleanly but instead would cut little of the surface but then would suddenly catch. Stainless steel behaved similarly; the metal would work-harden and not cut til enough pressure was applied, and then would suddenly give. The lathe or milling machine would have this “ka-chunk, ka-chunk” sound.

Anyway, I’ve now learned the hot-rolled steel puts out nasty splinters in the same way, and the gray splinters are harder to see than the nice shiny brass ones.

Next time, get the right metal for the right job. And get more band-aids.

After only a year of on-again, off-again work, I’ve got the tender for the live steam locomotive finished. The pictures don’t show just how big this is—it’s 18 inches long and weighs around 20 pounds. I had my doubts I’d ever get this far with the project,so I’m really proud that I’ve stuck with it and actually gotten something done.

Now, do I really want to build the rest of the engine? It’ll be at least twice as much time, and require much more careful work.

• Use lathe to machine the wheels and assorted other pieces
• Use mill to machine and drill all sorts of pieces.
• Bend sheet metal and stainless steel bar stock.
• Silver solder different assemblies—parts of wheelsets, handrails, etc.
• Soft-solder the tank body together, and make sure it won’t leak.

Everything was made from barstock or sheet metal except for the screws. Parts were made from either brass, steel, or stainless steel.

I must be learning something—three silver-soldered joints (brass to stainless steel), all three worked on the first try. (That’s tons better than a couple days ago where every other joint had to be redone.) The size of the piece can’t hurt, as getting some relatively small stainless steel rod up to 1200 degrees doesn’t take too long.

And I’m enjoying it. That’s fun to say for a skill that’s described in the books as a real pain in the ass. But I really like the silver soldered joint’s toughness—I love techniques that I can’t easily mess up later.

So one of the problems with metal is that it can be sharp, and if you’re handling it, it’s not hard to get cut. (There’s also issues of large spinning pieces of metal, pieces of metal flying off lathes, hot chips flying around, etc… but let’s leave that out.)

My last week of work has been fabricating parts from 0.040 inch brass sheet. I don’t have a power saw, so I’m doing all my cutting with a jeweler’s saw. I’ve also been bending curves into the sheet, and matching the curves to other pieces. I’m obviously working hard; I’ve gotten a few small cuts from the ragged edges and sharp pieces. Nothing too bad, but probably not good.

One of the books I got on machining specifically warns: “Your hands are your most important tool. Protect them.”

It’s time for me to be more careful—gloves when bending metal, breaking (filing) edges, etc.

I’m proud to say that I’m now a novice at machining. I can’t do precise work yet, and there’s lots I don’t know, but I do know enough to get started and make small objects with a lathe or mill.

My milestone last week to get a small steam engine kit running. I’d bought the kit last year when I’d first gotten a lathe, and immediately messed up some of the castings that came with the kit when I tried to drill holes with a cordless drill instead of a drill press or milling machine. I gave up on the project then, but finally pulled everything out and took another look at it.

My big advance was feeling competent enough to fabricate my own pieces. I may have messed up the passages that let steam into the cylinder, or I might have drilled holes wrong, but with a piece of aluminum rod, I managed to make a piece similar to my messed up casting. (Finally getting a milling attachment so I could drill straight holes certainly helped.)

So after a day or two of work, it was time to see if I could actually make something that worked. I hooked up the engine to an air compressor, turned the compressor on… and the steam engine started running back and forth as the air pushed the piston out and back. I even managed to play with the valve linkages a bit to adjust speed and power.

Woohoo!

Next step: make a tender for a live steam locomotive. I’ll need to be able to machine parts, silver solder, and anneal and form copper.

Here’s what the project would look like if I knew what I was doing:

http://phutcheson.net/a3_switcher.htm